Polymer composition for lubricant additives

ABSTRACT

A lubricating oil composition containing in combination an acylating agent substituted with a polymer of an alkene with 6 to 40 carbon atoms and an acylating agent substituted with polyisobutylene provides improved viscometric properties for dispersants used in internal combustion engines.

FIELD OF THE INVENTION

[0001] The present invention relates to an additive compositioncomprising in combination an acylating agent substituted with a polymerof an alkene with 6 to 40 carbon atoms; and an acylating agentsubstituted with polyisobutylene. The invention may be used inlubricating compositions especially for use in internal combustionengines.

BACKGROUND OF THE INVENTION

[0002] It is known to use dispersants in lubricating oils to dispersesoot and decrease the accumulation of sludge. Known dispersants includenitrogen containing derivatives of polyisobutylene-substituted succinicacid and derivatives of polydecene. Neither polyisobutylene-substitutedsuccinic acid nor polydecene derivatives exhibit both good lowtemperature and high temperature viscometrics.

[0003] Polyisobutylene-substituted succinic acid based dispersantsprovide good dispersant properties at high temperature. However, at lowtemperature, polyisobutylene succinic acid dispersants have poorviscometrics, causing lubricating oils to thicken. To compensate for thepoor low temperature viscometrics, viscosity modifiers are added tolubricating oils. The presence of the viscosity modifiers can lead tothe potential for soot deposits and the accumulation of sludge.

[0004] Polydecene-based dispersants are known for good low temperatureviscometric properties, specifically kinematic viscosity and dynamicviscosity. However, at high temperature polydecene-based dispersants areless effective than polyisobutylene-substituted succinic acid baseddispersants. Furthermore, polydecene is less attractive as a commercialproduct due to relatively high costs associated with its production.

[0005] GB Patent 1,439,567 discloses liquid organic compositions withdetergent properties by reacting a polymer of a straight chain 1-olefinhaving at least 10 carbons, with maleic anhydride to form thecorresponding polyalkenyl succinic anhydride. The polyalkenyl succinicanhydride is then reacted with an alkylene polyamine to form thecorresponding polyalkenyl succinimide.

[0006] U.S. Pat. Nos. 4,489,194 and 4,486,573 disclose compositionscontaining hydrocarbyl substituted carboxylic acylating agents made byreacting, (A) one or more alpha-beta olefinically unsaturated carboxylicacid reagents containing 2 to 20 carbon atoms, exclusive of thecarboxyl-based groups with (B) one or more high molecular weight olefinpolymers of more than 30 carbon atoms selected from the group consistingof (i) interpolymers of C₂₋₈ mono-1-olefins with C₁₂-C₃₀ mono-olefins,(ii) mixtures of (a) homopolymers and/or interpolymers of C₂₋₈mono-1-olefins with (b) homopolymers and/or interpolymers of C₁₂-C₃₀mono-olefins, and (iii) chlorinated or brominated analogs of (i) or(ii). This invention includes the acylated amine and/or alcoholderivatives of these hydrocarbyl-substituted carboxylic acid acylatingagents and their use in lubricants and normally liquid fuels.

[0007] PCT publication 99/46354 discloses the reaction products ofmaleic anhydride and oligoalkenes obtained through oligomerisation oflinear C₈- to C₁₂-1-alkenes. The linear C₈- to C₁₂-1-alkenes containvinylidene double bond fractions above 30% and have a number averagemolecular weight from 1000 to 20,000.

[0008] It would be desirable to have a composition with dispersancyproperties including good high and low temperature viscometrics, capableof improving seal compatability, capable of reducing the amount ofvolatile oils of lubricating viscosity used and capable of decreasingthe accumulation of sludge and/or soot deposits.

SUMMARY OF THE INVENTION

[0009] The present invention provides a composition comprising:

[0010] (a) an acylating agent containing a substituent of a polymer ofan alkene having about 6 to about 40 carbon atoms; and

[0011] (b) an acylating agent containing a polyisobutylene substituent;provided that the weight percent ratio of the alkene polymer substituentto the polyisobutylene substituent in the composition is about 25:75 toabout 75:25. The invention further provides a composition comprising thereaction product of:

[0012] (a) an acylating agent containing a substituent of a polymer ofan alkene having about 6 to about 40 carbon atoms; and

[0013] (b) an acylating agent containing a polyisobutylene substituent;and at least one compound selected from the group consisting of amines,alcohols, aminoalcohols and mixtures thereof, provided that the weightpercent ratio of the alkene polymer substituent to the polyisobutylenesubstituent in the composition is about 25:75 to about 75:25.

[0014] The invention further provides a composition comprising:

[0015] (a) an acylating agent containing a substituent of a polymer ofan alkene having 6 to 11 carbons atoms; and

[0016] (b) an acylating agent containing a polyisobutylene substituent;

[0017] provided that the weight percent ratio of the polyalkenesubstituent to the polyisobutylene substituent in the composition isabout 5:95 to about 95:5.

[0018] The invention further provides a method for preparing anacylating agent composition, comprising reacting a carboxylic acidreactant with a mixture of an alkene polymer of 6 to about 40 carbonatoms and a polyisobutylene, wherein the weight ratios of the alkenepolymer and the polyisobutylene employed are about 25:75 to about 75:25.

[0019] The invention further provides a method for preparing anacylating agent composition, comprising reacting a carboxylic acidreactant with an alkene polymer of 6 to about 40 carbon atoms, andseparately reacting a carboxylic acid reactant with a polyisobutylene,and subsequently combining the reaction products; wherein the weightratios of the alkene polymer and the polyisobutylene employed are about25:75 to about 75:25.

[0020] The invention further provides a method for preparing adispersant composition, comprising mixing together:

[0021] (a) the reaction product of an acylating agent containing asubstituent of a polymer of an alkene having about 6 to about 40 carbonatoms with an amine, alcohol, aminoalcohol, or mixtures thereof; and

[0022] the reaction product of an acylating agent containing apolyisobutylene substituent with an amine, alcohol, aminoalcohol, ormixtures thereof; provided that the weight percent ratio of the alkenepolymer substituent to the polyisobutylene substituent in thecomposition is about 25:75 to about 75:25.

[0023] The invention further provides a method for lubricating aninternal combustion engine, comprising supplying thereto a lubricantcomprising the composition as described herein.

[0024] The present invention further provides a composition capable ofproviding good high temperature and low temperature viscometrics. It canfurther lead to a decrease in sludge accumulation and soot deposits. Itfurther provides compositions capable of decreasing the amount ofviscosity modifier in lubricating oils. It further provides compositionscapable of reducing the amount of volatile oils of lubricating viscosityused and capable of imparting improved seal compatability.

DETAILED DESCRIPTION OF THE INVENTION

[0025] In one aspect, the composition of the present inventioncomprises:

[0026] (a) an acylating agent containing a substituent of a polymer ofan alkene having about 6 to about 40 carbon atoms; and

[0027] (b) an acylating agent containing a polyisobutylene substituent;provided that the weight percent ratio of the alkene polymer substituentto the polyisobutylene substituent in the composition is about 25:75 toabout 75:25.

[0028] Preferably the weight percent ratio of alkene polymer topolyisobutylene ratio is 30:70 to 70:30, more preferably 35:65 to 65:35,more preferably 40:60 to 60:40 and most preferably 45:55 to 55:45.

[0029] The alkene comprises carbon atoms ranging from a lower value ofcarbon atoms of 6, 7, 8, 9 or 10; and an upper value of 40, 30, 20, 18,16, 14 or 11 carbon atoms, or any combinations of lower and highervalues, e.g., 6-40, 6-20, 6-11, 8-40, 8-20, or 8-11.

[0030] In an alternative embodiment, the composition comprises:

[0031] an acylating agent substituted with a polymer of an alkene having6 to 11 carbons atoms; and

[0032] an acylating agent substituted with a polyisobutylene; providedthat the weight percent ratio of the alkene polymer to thepolyisobutylene in the composition is 5:95 to 95:5.

[0033] Preferably the alkene polymer with 6 to 11 carbons atoms and thepolyisobutylene are present in a weight ratio of 10:90 to 90:10, morepreferably, 20:80 to 80:20, more preferably 25:75 to 75 to 25, even morepreferably 30:70 to 70:30, even more preferably 35:65 to 65:35, evenmore preferably 40:60 to 60:40 and most preferably 45:55 to 55:45.

[0034] The polyalkene preferably contains a vinylidene double bond.Preferably the fraction of polyalkene molecules containing thevinylidene double bond is at least 25%, more preferably at least 30%,even more preferably at least 45%, even more preferably at least 55% andmost preferably at least 70%.

[0035] Examples of suitable alkenes include monomers selected from thegroup consisting of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene,1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene,1-henicosene, 1-docosene, 1-tetracosene, 1 -pentacosene, 1-hexacosene,1-octacosene, 1-nonacosene and mixtures thereof. A preferred alkene is1-decene.

[0036] Polyisobutylene is derived from isobutylene. It preferablycontains a vinylidene double bond. Preferably the fraction ofpolyisobutylene molecules containing a vinylidene double bond is atleast 25%, more preferably at least 30%, even more preferably at least45%, even more preferably at least 55% and most preferably at least 70%.

[0037] The number average molecular weight of the substituents (a) and(b) of the invention can be controlled using a variety of techniquessuch as reaction temperature, initiators, monomer concentration and typeof chain transfer agent. The number average molecular weight of thesubstituents of each (a) and (b) is preferably 350 to 25,000, morepreferably 500 to 15,000, and most preferably 1,000 to 5,000.

[0038] As used herein, the term “hydrocarbyl substituent” or“hydrocarbyl group” is used in its ordinary sense, which is known tothose skilled in the art. Specifically, it refers to a group having acarbon atom directly attached to the remainder of the molecule andhaving predominantly hydrocarbon character. Examples of hydrocarbylgroups include:

[0039] (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl oralkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, andaromatic-, aliphatic-, and alicyclic-substituted aromatic substituents,as well as cyclic substituents wherein the ring is completed throughanother portion of the molecule (e.g., two substituents together form aring);

[0040] (2) substituted hydrocarbon substituents, that is, substituentscontaining non-hydrocarbon groups which, in the context of thisinvention, do not alter the predominantly hydrocarbon substituent (e.g.,halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto,alkylmercapto, nitro, nitroso, and sulfoxy);

[0041] (3) hetero substituents, that is, substituents which, whilehaving a predominantly hydrocarbon character, in the context of thisinvention, contain other than carbon in a ring or chain otherwisecomposed of carbon atoms. Heteroatoms include sulphur, oxygen, nitrogen,and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. Ingeneral, no more than two, preferably no more than one, non-hydrocarbonsubstituent will be present for every ten carbon atoms in thehydrocarbyl group; typically, there will be no non-hydrocarbonsubstituents in the hydrocarbyl group.

[0042] Acylating Agents

[0043] The acylating agents (which are substituted by theabove-described polymers) include monobasic or polybasic carboxylicacids or reactive equivalents thereof. Reactive equivalents ofcarboxylic acids include anhydrides, esters, acylated nitrogen, acylhalide, nitriles, metal salts or mixtures thereof. Among these,anhydrides, particularly of diacids, are preferred.

[0044] Monobasic carboxylic acids include those represented by theformula:

[0045] wherein R¹ is hydrogen or hydrocarbyl containing 1 to 20,preferably 1 to 10, more preferably 1 to 5 and most preferably 1 to 2carbon atoms; and R² is hydrogen or alkyl with 1 to 6, preferably 1 to 4and most preferably 1 to 2 carbon atoms.

[0046] Monobasic carboxylic acids and derivatives thereof include(meth)acrylic acid, cinnamic acid, crotonic acid, 3-phenylpropenoicacid, α,β-decenoic acid, glyoxylic acid and mixtures thereof. (Theexpression “(meth)acrylic” is intended to encompass both acrylic andmethacrylic.)

[0047] Dibasic carboxylic acids and derivatives thereof include fumaricacid, maleic acid, mesaconic acid, itaconic acid, and citraconic acid.In one embodiment the derivative of a dibasic carboxylic acid is maleicanhydride.

[0048] In one embodiment the carboxylic acid includes glyoxylic acid oran ester thereof, or the hemiacetals of any of them. A preferred classof glyoxylic acid derivatives are glyoxylic acid esters. Examples ofsuitable glyoxylic acid esters include methyl glyoxylate, ethylglyoxylate, n-propyl glyoxylate, isopropyl glyoxylate, n-butylglyoxylate, isobutyl glyoxylate, pentyl glyoxylate, hexyl glyoxylate,heptyl glyoxylate, octyl glyoxylate, nonyl glyoxylate, decyl glyoxylate,undecyl glyoxylate, dodecyl glyoxylate, tridecyl glyoxylate, tetradecylglyoxylate, pentadecyl glyoxylate, hexadecyl glyoxylate, heptadecylglyoxylate, octadecyl glyoxylate, nonadecyl glyoxylate, icosylglyoxylate, stearyl glyoxylate, palmityl glyoxylate, hemiacetalglyoxylate esters such as glyoxylic methanol ester hemiacetals andmixtures thereof.

[0049] Preferred acylating agents are selected from the group consistingof maleic acid, maleic anhydride, (meth) acrylic acid, itaconic acid,fumaric acid, glyoxylic acid and mixtures thereof.

[0050] In one aspect of the present invention the composition comprisesthe reaction product of:

[0051] (a) an acylating agent containing a substituent of a polymer ofan alkene having about 6 to about 40 carbon atoms; and

[0052] (b) an acylating agent containing a polyisobutylene substituent;and

[0053] (c) at least one compound selected from the group consisting ofamines, alcohols, aminoalcohols and mixtures thereof,

[0054] provided that the weight percent ratio of the alkene polymersubstituent to the polyisobutylene substituent in the composition isabout 25:75 to about 75:25

[0055] Process

[0056] The compositions of the invention can be prepared using thefollowing methods:

[0057] (I) For preparing an acylating agent composition, reacting acarboxylic acid reactant with a mixture of an alkene polymer of 6 toabout 40 carbon atoms and a polyisobutylene, wherein the weight ratiosof the alkene polymer and the polyisobutylene employed are about 25:75to about 75:25.

[0058] (II) For preparing an acylating agent composition, reacting acarboxylic acid reactant with an alkene polymer of 6 to about 40 carbonatoms, and separately reacting a carboxylic acid reactant with apolyisobutylene, and subsequently combining the reaction products;wherein the weight ratios of the alkene polymer and the polyisobutyleneemployed are about 25:75 to about 75:25

[0059] (III) For preparing a dispersant composition, mixing together:

[0060] the reaction product of an acylating agent containing asubstituent of a polymer of an alkene having about 6 to about 40 carbonatoms with an amine, alcohol, aminoalcohol, or mixtures thereof; and

[0061] the reaction product of an acylating agent containing apolyisobutylene substituent with an amine, alcohol, aminoalcohol, ormixtures thereof;

[0062] provided that the weight percent ratio of the alkene polymersubstituent to the polyisobutylene substituent in the composition isabout 25:75 to about 75:25.

[0063] The methods (I), (II) and (III) are typically conducted in thetemperature range of 100° C. to 300° C., preferably 130° C to 270° C.and more preferably 150° C. to 2500° C.

[0064] In one embodiment, the methods (I) and (II) may contain a halogenselected from the group consisting of chlorine, bromine, iodine andmixtures thereof. The reactions carried out in the presence of halogencan take place in the temperature range of 100° C. to 300° C.,preferably 110° C. to 250° C. and more preferably 120° C. to 220° C.

[0065] (IV) The invention further includes a method for reacting (I) or(II) with compounds selected from the group consisting of amines,alcohols, aminoalcohols and mixtures thereof. The resulting product hasdispersant properties.

[0066] Reaction Products with Amines, Alcohols and Aminoalcohols

[0067] Amines suitable for reacting with the mixture (a) and (b) includemonoamines and polyamines, preferably polyamines. The polyamines may belinear or branched and are selected from the group consisting ofalkylenepolyamine, cycloaliphatic polyamine, heterocyclic polyamines andmixtures thereof.

[0068] In one embodiment the alkylenepolyamines are selected from thegroup consisting of ethylenepolyamines, propylenepolyamines,butylenepolyamines and mixtures thereof. Examples of propylenepolyaminesinclude propylenediamine, dipropylenetriamine or mixtures thereof.Ethylenepolyamines are preferred and specific compounds includeethylenediamine, diethylenetriamine, triethylenetetramine,tetraethylenepentamine, pentaethylenehexamine, polyamine still bottomsand so-called “heavy amines” such as HPA-X™ from Union Carbide andE-100™ from Dow, and mixtures thereof.

[0069] In one embodiment the polyamines are α,β-diaminoalkanes. Suitableα,β-diaminoalkanes include diaminopropanes, diaminobutanes or mixturesthereof. Specific diaminoalkanes are selected from the group consistingof N-(2-aminoethyl)-1,3-propane diamine,3,3′-diamine-N-methyldipropylamine, tris(2-aminoethyl)amine,N,N-bis(3-aminopropyl)-1,3-propane diamine,N,N′-1,2-ethanediylbis-(1,3-propane diamine) and mixtures thereof.

[0070] Other suitable polyamines include di-(trimethylene)triamine,piperazine, diaminocyclohexanes and mixtures thereof.

[0071] Alcohols suitable for reacting with the mixture (a) and (b)include monohydric and polyhydric alcohols. Polyhydric alcohols arepreferred with 2 to 10, preferably 2 to 6 hydroxy groups. The alcoholscan be aliphatic, cycloaliphatic, aromatic, or heterocyclic.

[0072] Suitable alcohols include dihydroxypropanes, dihydroxybutanes,dihydroxy-pentanes, glycerine, trihydroxypropanes, trihydroxybutanes,trihydroxypentanes and mixtures thereof.

[0073] In one embodiment the preferred alcohol is a polyol. Suitablepolyols include ethylene glycol, propylene glycol, butylene glycol,pentaerthyritol, mannitol, sorbitol, glycerol, erythritol,2-hydroxymethyl-2-methyl-1,3-propanediol (trimethylolethane),2-ethyl-2-(hydroxymethyl)-1,3-propanediol (trimethylolpropane),1,2,4-hexanetriol and mixtures thereof.

[0074] Aminoalcohols suitable for the invention contain 1 to 6 andpreferably 1 to 3 hydroxy groups; and 1 to 8 and preferably 1 to 2 aminegroups.

[0075] The aminoalcohols of the invention can be selected from the groupconsisting of ethanolamine, isopropanolamine, diethanolamine,triethanolamine, diethyl-ethanolamine, dimethylethanolamine,dibutylethanolamine, 3-amino-1,2-propanediol; serinol;2-amino-2-methyl-1,3-propanediol; tris(hydroxymethyl)-aminomethane;1-amino-1-deoxy-D-sorbitol; diethanol amine; diisopropanolamine;N-methyl-N,N-diethanol amine; triethanolamine;N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene-diamine,2-amino-2-methyl-1-propanol, 2-dimethylamino-methyl-1-propanediol,2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl -1,3-propanediol,2-amino-1-butanol and mixtures thereof. Preferably the aminoalcohol isethanolamine.

[0076] Oil of Lubricating Viscosity

[0077] The composition of the present invention can be added to an oilof lubricating viscosity. Such oils include natural and synthetic oils,oil derived from hydrocracking, hydrogenation, hydrofinishing,unrefined, refined and re-refined oils, and mixtures thereof.

[0078] Unrefined oils are those obtained directly from a natural orsynthetic source generally without (or with little) further purificationtreatment.

[0079] Refined oils are similar to the unrefined oils except they havebeen further treated in one or more purification steps to improve one ormore properties. Purification techniques are known in the art andinclude solvent extraction, secondary distillation, acid or baseextraction, filtration, percolation and the like.

[0080] Re-refined oils are also known as reclaimed or reprocessed oils,and are obtained by processes similar to those used to obtain refinedoils and often are additionally processed by techniques directed toremoval of spent additives and oil breakdown products.

[0081] Natural oils useful in making the inventive lubricants includeanimal oils, vegetable oils (e.g., castor oil, lard oil), minerallubricating oils such as liquid petroleum oils and solvent-treated oracid-treated mineral lubricating oils of the paraffinic, naphthenic ormixed paraffinic-naphthenic types and oils derived from coal or shale ormixtures thereof.

[0082] Synthetic lubricating oils are useful and include hydrocarbonoils such as polymerised and interpolymerised olefins (e.g.,polybutylenes, polypropylenes, propyleneisobutylene copolymers);poly(1-hexenes), poly(1-octenes), poly(1-decenes), and mixtures thereof;alkyl-benzenes (e.g. dodecylbenzenes, tetradecylbenzenes,dinonylbenzenes, di-(2-ethylhexyl)-benzenes); polyphenyls (e.g.,biphenyls, terphenyls, alkylated polyphenyls); alkylated diphenyl ethersand alkylated diphenyl sulphides and the derivatives, analogs andhomologs thereof and mixtures thereof. Polyalphaolefins are typicallyhydrogenated when used as lubricating oils.

[0083] Other synthetic lubricating oils include but are not limited toliquid esters of phosphorus-containing acids (e.g., tricresyl phosphate,trioctyl phosphate, and the diethyl ester of decane phosphonic acid),and polymeric tetrahydrofurans. Synthetic oils may be produced byFischer-Tropsch reactions and typically may be hydroisomerisedFischer-Tropsch hydrocarbons or waxes.

[0084] Oils of lubricating viscosity can also be defined as specified inthe American Petroleum Institute (API) Base Oil InterchangeabilityGuidelines. The five base oil groups are as follows: Group I (sulphurcontent >0.03 wt %, and/or <90 wt % saturates, viscosity index 80-120);Group II (sulphur content ≦0.03 wt %, and ≧90 wt % saturates, viscosityindex 80-120); Group III (sulphur content ≦0.03 wt %, and ≧90 wt %saturates, viscosity index ≧120); Group IV (all polyalphaolefins(PAOs)); and Group V (all others not included in Groups I, II, III, orIV). Preferably the oil of lubricating viscosity is selected from an APIGroup II, Group III, Group IV, Group V oil and mixtures thereof.

[0085] The oil of lubricating viscosity is typically present at 30 to99.9, preferably 55 to 99, and more preferably 65 to 96 and mostpreferably 73 to 95 weight percent of the lubricating oil composition.

[0086] In a typical lubricating composition comprising, the compositionsof the invention can be present in an oil of lubricating viscosity inamounts of 0.1 to 30, preferably 0.5 to 20, more preferably 1 to 15, andmost preferably 5 to 12 weight percent of the lubricating oilcomposition.

[0087] If the present invention is in the form of a concentrate (whichcan be combined with additional oil to form, in whole or in part, afinished lubricant), the ratio of each of the above-mentioneddispersant, as well as other components, to diluent oil is typically inthe range of 99:1 to 10:90 by weight.

[0088] Optional Additives

[0089] Optionally the lubricating composition can include additivesselected from the group consisting of antioxidants, metal deactivators,detergents, antiwear agents, dispersants, antiscuffing agents, extremepressure agents, foam inhibitors, demulsifiers, viscosity modifiers,pour point depressants and mixtures thereof.

[0090] The total combined amount of the optional additives present canbe 0 to 40, preferably 0.5 to 25, more preferably 3 to 20 and mostpreferably 5 to 15 weight percent of the lubricating oil composition.

[0091] Antioxidants

[0092] Antioxidants include hindered phenols represented by the formula:

[0093] wherein R³ and R⁴ are independently branched or linear alkylgroups containing about 1 to 24, preferably 4 to 18, and most preferably4 to 12 carbon atoms. R³ and R⁴ can be either straight or branchedchain; branched is preferred. Preferably the phenol is butyl substitutedcontaining two t-butyl groups. When the t-butyl groups occupy the2,6-positions, the phenol is sterically hindered. Q is hydrogen orhydrocarbyl. Examples of suitable hydrocarbyl groups include2-ethylhexyl, n-butyl, dodecyl or mixtures thereof.

[0094] Other optional sterically hindered phenols suitable for theinvention include those represented by the formulae:

[0095] wherein R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰ are either straight or branchedchain and contain 4 to 18, preferably 4 to 12 carbon atoms. Preferablythe phenol is butyl substituted. R¹¹ and R¹² are independently hydrogenor hydrocarbyl; preferably R¹¹ and R¹² are arylalkyl or alkyl groups.The alkyl groups can be linear or branched, linear being preferred. R¹¹and R¹² are preferably in the para position. The arylalkyl or alkylgroups typically contain 1 to 15, preferably 1 to 10, and morepreferably 1 to 5 carbon atoms. The bridging group Y includes —CH₂—(methylene bridge) or —CH₂OCH₂— (ether bridge).

[0096] Examples of methylene-bridged sterically hindered phenols include4,4′-methylene-bis-(6-tert-butyl o-cresol),4,4′-methylene-bis-(2-tert-amyl-o-cresol),2,2′-methylene-bis-(4-methyl-6-tert-butylphenol), 4,4′-methylene-bis-(2,6-di-tertbutyl-phenol) and mixtures thereof.

[0097] In one embodiment the antioxidant is a hindered ester-substitutedphenol represented by the formula:

[0098] wherein R¹³, R¹⁴ and R¹⁵ are straight or branched alkyl groupcontaining 2 to 22, preferably 2 to 18, more preferably 4 to 8 carbonatoms. Specific examples include of alkyl groups include 2-ethylhexyl orn-butyl ester, dodecyl and mixtures thereof.

[0099] Another class of antioxidant is alkylated diphenylamines that canbe represented by the following formula:

[0100] wherein R¹⁶ and R¹⁷ are independently hydrogen or hydrocarbyl,preferably arylalkyl or alkyl groups. The arylalkyl groups contain 5 to20, preferably 6 to 10 carbons atoms. The alkyl groups can be linear orbranched, preferably linear; the alkyl group contains 1 to 24,preferably 2 to 18 and most preferably 4 to 12 carbon atoms; and z isindependently 0, 1, 2, or 3, provided that at least one aromatic ringcontains a hydrocarbyl group. Preferred alkylated diphenylamines includebis-nonylated diphenylamine and bis-octylated diphenylamine and mixturesthereof.

[0101] Metal Deactivators

[0102] Metal deactivators can be used to neutralise the catalytic effectof metal for promoting oxidation in lubricating oil. Examples of metaldeactivators include derivatives of benzotriazoles, benzimidazoles,2-alkyldithiobenzimidazoles, 2-alkyl-dithiobenzothiazoles,2-(N,N-dialkyldithiocarbamoyl)benzothiazoles,2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,2,5-bis(N,N-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles,2-alkyldithio-5-mercapto thiadiazoles and mixtures thereof.

[0103] Preferably the metal deactivator is a hydrocarbyl substitutedbenzotriazole compound. The benzotriazole compounds can includehydrocarbyl substitutions in at least one of the following ringpositions 1- or 2- or 4- or 5- or 6- or 7-. The hydrocarbyl groupscontain about 1 to about 30, preferably about 1 to about 15, morepreferably about 1 to about 7 carbon atoms, most preferably the metaldeactivator is 5-methylbenzotriazole, which may be used alone or incombination.

[0104] Detergents

[0105] Detergents are well-known and include neutral or overbased,carbonated or non-carbonated Newtonian or non-Newtonian, basic salts ofalkali, alkaline earth and transition metals with one or morehydrocarbyl sulphonic acid, carboxylic acid, phosphorus acid, mono-and/or di- thiophosphorus acid, alkyl phenol, sulphur coupled alkylphenol compounds, salixarates, saligenins or mixtures thereof. Commonlyused metals are sodium, potassium, calcium, magnesium, lithium ormixtures thereof. Most commonly used metals include sodium, magnesium,calcium and mixtures thereof. Overbased detergents are disclosed forinstance in U.S. Pat. No. 3,629,109.

[0106] Dispersants

[0107] Dispersants are often known as ashless-type dispersants because,prior to mixing in a lubricating oil composition, they do not containash-forming metals; and they do not normally contribute any ash formingmetals when added to a lubricant. Ashless type dispersants arecharacterised by a polar group attached to a relatively high molecularweight hydrocarbon chain. Typical ashless dispersants includeN-substituted long chain alkenyl succinimides. Examples of N-substitutedlong chain alkenyl succinimides include polyisobutylene succinimide withnumber average molecular weight in the range 350 to 5000, preferably 500to 3000. Succinimide dispersants and their preparation are disclosed,for instance, in U.S. Pat. No. 4,234,435.

[0108] Antiwear Agents

[0109] The lubricant may additionally contain an antiwear agent. Usefulantiwear agents include metal thiophosphates, especially zincdialkyldithiophosphates; phosphoric acid esters or salt thereof;phosphites; and phosphorus-containing carboxylic esters, ethers, andamides.

[0110] Antiscuffing Agents

[0111] The lubricant may also contain an antiscuffing agent.Antiscuffing agents that decrease adhesive wear are often sulphurcontaining compounds. Typically the sulphur containing compounds includeorganic sulphides and polysulphides, such as benzyldisulphide,bis-(chlorobenzyl) disulphide, dibutyl tetrasulphide, di-tertiary butylpolysulphide, sulphurised sperm oil, sulphurised methyl ester of oleicacid, sulphurised alkylphenol, sulphurised dipentene, sulphurisedterpene, sulphurised Diels-Alder adducts, alkyl sulphenyl N′N-dialkyldithiocarbamates, the reaction product of polyamines with polybasic acidesters, chlorobutyl esters of 2,3-dibromo-propoxyisobutyric acid,acetoxymethyl esters of dialkyl dithiocarbamic acid and acyloxyalkylethers of xanthogenic acids or mixtures thereof.

[0112] Extreme Pressure Agents

[0113] Extreme Pressure (EP) agents that are soluble in the oil includesulphur and chlorosulphur-containing EP agents, chlorinated hydrocarbonEP agents, phosphorus EP agents, and mixtures thereof. Examples of suchEP agents include compounds selected from the group consisting ofchlorinated wax, organic sulphides and polysulphides, such asbenzyldisulphide, bis-(chlorobenzyl) disulphide, dibutyl tetrasulphide,sulphurised sperm oil, sulphurised methyl ester of oleic acid,sulphurised alkylphenol, sulphurised dipentene, sulphurised terpene, andsulphurised Diels-Alder adducts; phosphosulphurised hydrocarbons, suchas the reaction product of phosphorus sulphide with turpentine or methyloleate, phosphorus esters such as the dihydrocarbon and trihydrocarbonphosphites, e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexylphosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecylphosphite, distearyl phosphite and polypropylene substituted phenolphosphite, metal thiocarbamates, such as zinc dioctyldithiocarbamate andbarium heptylphenol diacid, such as zinc dicyclohexyl phosphorodithioateand the zinc salts of a phosphorodithioic acid; amine salts of alkyl anddialkylphosphoric acids, including, for example, the amine salt of thereaction product of a dialkyldithiophosphoric acid with propylene oxide;and mixtures thereof.

[0114] Foam Inhibitors

[0115] Foam inhibitors are known and include organic silicones such aspolyacetates, dimethyl silicone, polysiloxanes, polyacrylates ormixtures thereof. Examples of foam inhibitors include polyethylacrylate,poly-2-ethylhexylacrylate, polyvinyl-acetate and mixtures thereof.

[0116] Demulsifiers

[0117] Demulsifiers are known and include derivatives of propyleneoxide, ethylene oxide, polyoxyalkylene alcohols, alkyl amines, aminoalcohols, diamines or polyamines reacted sequentially with ethyleneoxide or substituted ethylene oxides or mixtures thereof. Examples ofdemulsifiers include polyethylene glycols, poly(ethyleneoxides),poly(propylene oxides), (ethylene oxide-propylene oxide) polymers andmixtures thereof.

[0118] Pour Point Depressants

[0119] Pour point depressants are known and include esters of maleicanhydride-styrene copolymers, polymethacrylates; polyacrylates;polyacrylamides; condensation products of haloparaffin waxes andaromatic compounds; vinyl carboxylate polymers; and terpolymers ofdialkylfumarates, vinyl esters of fatty acids, ethylene-vinyl acetatecopolymers, alkyl phenol formaldehyde condensation resins, alkyl vinylethers and mixtures thereof.

[0120] Viscosity Modifiers

[0121] Viscosity modifiers are known and include copolymers ofstyrene-butadiene rubbers, ethylene-propylene polymers, polyisobutenes,hydrogenated styrene-isoprene polymers, hydrogenated radical isoprenepolymers, polymethacrylate acid esters, polyacrylate acid esters,polyalkyl styrenes, alkenyl aryl conjugated diene copolymers,polyolefins, polyalkylmethacrylates, esters of maleic anhydride-styrenecopolymers or mixtures thereof.

[0122] Industrial Application

[0123] The compositions of the present invention are useful as additivesin greases, gear oils, industrial fluids, hydraulic fluids, transmissionfluids, turbine oils, circulating oils, and engine oils. They areparticularly useful in lubricants for internal combustion engines, suchas diesel fuelled engines or gasoline fuelled engines. Such engines canbe lubricated by supplying thereto a lubricating oil compositioncomprising the components as described above.

[0124] The use of the lubricating oil compositions of the invention ininternal combustion engines will typically exhibit at least one improvedproperty selected from the group consisting of good high temperatureviscometrics, low temperature viscometrics, decrease in sludgeaccumulation, decrease in soot deposits, improved seal compatability,reduced amount of volatile oils of lubricating viscosity and a decreasein amount of viscosity modifier required, and improved sealcompatability. Improved seal compatibility can be revealed by improvedtensile strength, improved elongation strength and decreased hardness.

[0125] The following examples provide an illustration of the invention.These examples are non exhaustive and are not intended to limit thescope of the invention.

EXAMPLES Examples 1 to 3 and Reference Examples R1 and R2

[0126] Mixtures of polydecene (obtained from BP Amoco) with numberaverage molecular weight of 1656 and high vinylidene polyisobutylenewith number average molecular weight of 1510 are reacted with maleicanhydride. The mixtures of high vinylidene polydecene and highvinylidene polyisobutylene contain approximately 1600 g of sample withweight ratios of polydecene: polyisobutylene of 1600:0, 1200:400,800:800, 400:1200 and 0:1600 and are reacted with approximately 213.9 gof maleic anhydride. The reactants are heated to 203° C. over 3½ hoursand held at this temperature for twenty-four hours. The product of thereaction is then heated to 210° C. for one hour under vacuum at 0.67 kPa(5 mm Hg) to remove volatiles.

[0127] Approximately 600 g of the above reaction product is dissolved indiluent oil and heated to 110° C. under nitrogen. Approximately 34 g ofHPAX™(polyamine still bottoms) is added over 30 minutes and the reactionmixture is held at 110° C. for a further 30 minutes. The reaction isheated to 155° C. and held for 5 hours. The resulting product is cooledand filtered to produce a dispersant.

[0128] The dispersant is dissolved in a 5W-30 lubricating oil preparedcontaining 68.9 weight percent of Yubase™ 3050 API Group 3 base oil, 5mm²s⁻¹ (cSt) at 100° C. and 31.1 weight percent of PAO-6 Group 4 baseoil, 6 mm²s⁻¹ (cSt) at 100° C. Reference examples 1 and 2 contain 100 wt% of polyisobutylene succinimide and 100 wt % of polydecene succinimiderespectively. Examples 1 to 3 contain polyisobutylene succinimide:polydecene succinimide weight percent ratios of 25:75, 50:50 and 75:25respectively.

Examples 4 to 6 and Reference Examples R3 and R4

[0129] These samples are prepared in a similar process to examples 1 to3 and reference examples R1 to R2 except they are dissolved in Exxon100N base oil at 0.5 wt %.

Examples 7 to 10 and Reference Examples R5 to R8

[0130] These samples are prepared in a similar process to example 5except, 7 to 10 wt % of lubricating oil composition contains a 50:50mixture of the polyisobutylene:

[0131] polydecene dispersant. Reference examples R5 to R8 contain 7 to10 wt % of a polyisobutylene dispersant in 5W-30 grade lubricating oilcompositions containing 56 weight percent of API Group 4, PAO-4 baseoil, 4 mm²s⁻¹ (cSt) at 100° C., 30 weight percent of API Group 4, PAO-6base oil, 6 mm²s⁻¹ (cSt) at 100° C. and 13.6 weight percent of PL 3970API Group 5 base oil, 4.5 mm²s⁻¹ (cSt) at 100° C.

[0132] Test 1: Seal Performance

[0133] Seal compatibility tests are designed to evaluate the effect ofmotor oils on Parker-Pradifa™ FKM E-281 seal elastomers(fluoroelastomer). Six dumbbells of elastomer are suspended using amicro wire and glass separators are covered by at least 10 ml of oil.The test vessel is covered with aluminium foil and stored at 150° C. for96 hours. The elastomer is removed from the oil and tested forpercentage change in tensile strength, elongation at break, cracking (bybending) and hardness.

[0134] The results obtained for examples 1 to 3 and comparative examples1 and 2 are: Mixture Wt % Wt % Final Seal Test Values Poly- Polyiso-Elongation Hardness Ex. decene butylene Cracking Tensile (%) (%) R1 0100 Mild 8.1 170.0 71.0 1 25 75 None 8.5 172.2 71.0 2 50 50 Barely 10.0206.6 70.5 3 75 25 Barely 8.2 175.6 71.0 R2 100 0 Moderate 7.8 168.872.2

[0135] The analysis indicates seals treated with compositions containinga weight percent ratio of polydecene to polyisobutylene 25:75 to 75:25have decreased amounts of cracking compared with comparative examples 1and 2. Furthermore, other seal properties such as tensile strength,elongation and hardness are improved when compositions containing aweight percent ratio of polydecene to polyisobutylene 25:75 to 75:25 areused. Overall the analysis indicates dispersants of the inventionprovide improved seal properties compared with conventional dispersants.

[0136] Test 2: Sludge Performance

[0137] A dispersant sample is dissolved in Exxon 100N diluent oil at sixconcentrations between 0.125 wt % and 0.004 wt % and mixed with a sludgesample. The resulting mixture is allowed to stand for 24 hours. Theamount of sludge remaining in solution at the lowest concentration ofdispersant is measured.

[0138] The sludge ratio is calculated by dividing the amount of sludgeby the weight percent of the dispersant used. The higher the sludgeratio indicates a lower concentration of dispersant is better able tokeep the sludge in solution. The results obtained for examples 1 to 3and comparative examples 1 and 2 are: Mixture Wt % Wt % Sludge ExamplePolydecene Polyisobutylene Ratio R3 0 100 225 4 25 75 225 5 50 50 175 675 25 125 R4 100 0 63

[0139] The analysis indicates compositions with weight percent ratios ofpolydecene to polyisobutylene between 25:75 and 75:25 have gooddispersancy properties. Furthermore, better results are obtained whenthe polydecene to polyisobutylene is between 25:75 and 50:50.

[0140] Test 3: High Temperature Viscometrics at Constant Treat Rates

[0141] The KV100 (kinematic viscosity) value is determined by measuringthe time for 40 g of oil to flow under gravity through a calibratedglass capillary viscometer.

[0142] Examples 4-6 and comparative examples R3-R4 demonstrate the hightemperature viscometrics for compositions of the invention with adispersant treat rate held at 9 wt %. The results obtained are: MixtureWt % Wt % Example Polydecene Polyisobutylene KV 100° C. R3 0 100 13.10 425 75 12.73 5 50 50 12.01 6 75 25 11.69 R4 100 0 11.01

[0143] The analysis indicates only examples with polydecene substituentin the dispersant composition maintain KV100° C. at 12.5 mm²s⁻¹ (cSt) orless. By interpolating the KV100° C. data, approximately 31 wt % ofpolydecene substituent is required in dispersant compositions with a 9wt % treat rate to maintain KV100° C. at 12.5 mm²s⁻¹ (cSt) or less.

[0144] Test 4: High Temperature Viscometrics at Varied Treat Rates

[0145] Experimental procedure is as is described in Test 3. The resultsobtained for examples 7 to 10 and reference examples R5-R8 are: ExampleWt % Dispersant KV 100° C. R5 7 12.03 R6 8 12.63 R7 9 13.1 R8 10 13.68 77 11.13 8 8 11.69 9 9 12.01 10 10 12.44

[0146] The analysis indicates to keep the oil at a viscosity of 12.5mm²s⁻¹ (cSt) or less, the maximum amount of polyisobutylene-only typedispersants (reference examples R5-R8) that can be used is 7 wt %(example R5). However, using compositions of the invention with a wt %ratio of polyisobutylene: dispersant composition of 50:50 allows theamount of dispersant to be increased to 10 wt % (example9).

[0147] Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like are to be understood as modified by the word“about.” Unless otherwise indicated, each chemical or compositionreferred to herein should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent oil, which may becustomarily present in the commercial material, unless otherwiseindicated. It is to be understood that the upper and lower amount,range, and ratio limits set forth herein may be independently combined.Similarly, the ranges and amounts for each element of the invention canbe used together with ranges or amounts for any of the other elements.As used herein, the expression “consisting essentially of” permits theinclusion of substances that do not materially affect the basic andnovel characteristics of the composition under consideration.

[0148] While the invention has been explained, it is to be understoodthat various modifications thereof will become apparent to those skilledin the art upon reading the specification. Therefore, it is to beunderstood that the invention disclosed herein is intended to cover suchmodifications as fall within the scope of the appended claims.

What is claimed is:
 1. A composition comprising: (a) an acylating agentcontaining a substituent of a polymer of an alkene having about 6 toabout 40 carbon atoms; and (b) an acylating agent containing apolyisobutylene substituent; provided that the weight percent ratio ofthe alkene polymer substituent to the polyisobutylene substituent in thecomposition is about 25:75 to about 75:25.
 2. The composition of claim 1wherein the alkene comprisies a mixtures of alpha-olefins.
 3. Thecomposition of claim 1 wherein the alkene contains about 6 to about 18carbon atoms.
 4. The composition of claim 1 wherein the alkene containsabout 6 to 11 carbon atoms.
 5. The composition of claim 1, wherein theacylating agents are prepared by the reaction of a carboxylic acid orreactive equivalents thereof, with an alkene polymer of about 6 to about40 carbon atoms and with a polyisobutylene.
 6. The composition of claim5 wherein the alkene polymer and the polyisobutylene are mixed togetherand reacted with the carboxylic acid reactant.
 7. The composition ofclaim 6 wherein the alkene polymer and the polyisobutylene areseparately reacted with the carboxylic acid reactant, and the resultingproducts are mixed together.
 8. The composition of claim 5 wherein thealkene polymer contains a vinylidene double bond.
 9. The composition ofclaim 5 wherein at least about 30% of the polyisobutylene moleculescontain a vinylidene double bond.
 10. The composition of claim 5 whereinthe carboxylic acid reactant is selected from the group consisting ofmaleic acid, maleic anhydride, acrylic acid, methacrylic acid, itaconicacid, fumaric acid, glyoxylic acid or an ester thereof, and mixturesthereof.
 11. A composition comprising the reaction product of: anacylating agent containing a substituent of a polymer of an alkenehaving about 6 to about 40 carbon atoms; and an acylating agentcontaining a polyisobutylene substituent; and at least one compoundselected from the group consisting of amines, alcohols, aminoalcoholsand mixtures thereof, provided that the weight percent ratio of thealkene polymer substituent to the polyisobutylene substituent in thecomposition is about 25:75 to about 75:25.
 12. The composition of claim11 wherein the amine is a polyamine.
 13. The composition of claim 1further comprising an oil of lubricating viscosity.
 14. The compositionof claim 11 further comprising an oil of lubricating viscosity.
 15. Thecomposition of claim 1 wherein the oil of lubricating viscosity isselected from API Group II, Group III, Group IV, and Group V oils andmixtures thereof.
 16. The composition of claim 11 wherein the oil oflubricating viscosity is selected from API Group II, Group III, GroupIV, and Group V oils and mixtures thereof.
 17. The composition of claim1, further comprising at least one additive selected from the groupconsisting of antioxidants, metal deactivators, detergents, dispersants,antiwear agents, antiscuffing agents, extreme pressure agents, foaminhibitors, demulsifiers, viscosity modifiers, pour point depressants,and mixtures thereof.
 18. The composition of claim 11, furthercomprising at least one additive selected from the group consisting ofantioxidants, metal deactivators, detergents, dispersants, antiwearagents, antiscuffing agents, extreme pressure agents, foam inhibitors,demulsifiers, viscosity modifiers, pour point depressants, and mixturesthereof.
 19. A composition comprising: (a) an acylating agent containinga substituent of a polymer of an alkene having 6 to 11 carbons atoms;and (b) an acylating agent containing a polyisobutylene substituent;provided that the weight percent ratio of the alkene polymer substituentto the polyisobutylene substituent in the composition is about 5:95 toabout 95:5.
 20. The composition of claim 19 wherein the alkene polymerwith 6 to 11 carbons atoms is polydecene.
 21. A composition comprisingthe reaction product of the composition of claim 19 with an amine, analcohol, an aminoalcohol, or mixtures thereof.
 22. The composition ofclaim 19, further comprising at least one additive selected from thegroup consisting of antioxidants, metal deactivators, detergents,dispersants, antiwear agents, antiscuffing agents, extreme pressureagents, foam inhibitors, demulsifiers, viscosity modifiers, pour pointdepressants and mixtures thereof.
 23. The composition of claim 21,further comprising at least one additive selected from the groupconsisting of antioxidants, metal deactivators, detergents, dispersants,antiwear agents, antiscuffing agents, extreme pressure agents, foaminhibitors, demulsifiers, viscosity modifiers, pour point depressantsand mixtures thereof.
 24. A method for lubricating an internalcombustion engine, comprising supplying thereto the lubricating oilcomposition of claim
 14. 25. A method for preparing an acylating agentcomposition, comprising reacting a carboxylic acid reactant with amixture of an alkene polymer of 6 to about 40 carbon atoms and apolyisobutylene, wherein the weight ratios of the alkene polymer and thepolyisobutylene employed are about 25:75 to about 75:25.
 26. A methodfor preparing an acylating agent composition, comprising reacting acarboxylic acid reactant with an alkene polymer of 6 to about 40 carbonatoms, and separately reacting a carboxylic acid reactant with apolyisobutylene, and subsequently combining the reaction products;wherein the weight ratios of the alkene polymer and the polyisobutyleneemployed are about 25:75 to about 75:25.
 27. A method for preparing adispersant composition, comprising further reacting the acylating agentcomposition prepared by the method of claim 25 with an amine, analcohol, an aminoalcohol, or mixtures thereof.
 28. A method forpreparing a dispersant composition, comprising further reacting theacylating agent composition prepared by the method of claim 26 with anamine, an alcohol, an aminoalcohol, or mixtures thereof.
 29. A methodfor preparing a dispersant composition, comprising mixing together: (a)the reaction product of an acylating agent containing a substituent of apolymer of an alkene having about 6 to about 40 carbon atoms with anamine, alcohol, aminoalcohol, or mixtures thereof; and (b) the reactionproduct of an acylating agent containing a polyisobutylene substituentwith an amine, alcohol, aminoalcohol, or mixtures thereof; provided thatthe weight percent ratio of the alkene polymer substituent to thepolyisobutylene substituent in the composition is about 25:75 to about75:25.